Central Asian Journal of Water Research (2017) 3(2): 3-11 Special Issue on Water Use Management Challenges in Central Asia and Afghanistan © Author(s) 2017. Assessment of water quality and quantity trends in Kabul aquifers with an outline for future drinking water supplies Abdulhalim Zaryab1*, Ali Reza Noori1, Kai Wegerich2, Bjørn Kløve3 1Kabul Polytechnic University, Kabul, Afghanistan 2Martin-Luther-University Halle-Wittenberg, Institute for Geosciences and Geography, Germany 3University of Oulu, Faculty of Technology, Water Resources and Environmental Engineering Research Unit, Finland *Corresponding author. Email address: [email protected] Abstract The water supply to Kabul city is at serious risk due to groundwater over abstraction and severe contamination by sewage. The water overuse is partly due to poor management and a long period of war, and instability in Afghanistan. In recent years shallow wells have been installed and financed by aid programmes, but this, along with high population increase has also lead to over-use of groundwater resources. The current water supply of about 85% inhabitants depends exclusively on local, individual groundwater sources, obtained predominantly from shallow aquifers, mainly, by hand-pumps. The paper analyses the status and trends of the Kabul groundwater system and assesses new solutions to meet the future water supply demand. The status of groundwater shows that groundwater levels are declining quickly (1 m/year) and several wells are already dry. Moreover, water quality analyses of the Kabul aquifers show a negative trend in groundwater quality in respect to concentration of nitrates, borates and faecal microbes (indicated by the coliform bacteria). This pollution exceeds the maximum permissible values determined by the WHO. To provide new solutions for Kabul city, a master plan for future water resources has been developed and this is further discussed. Keywords: water supply, aid programmes, aquifer, overuse, nitrate, pathogens. 1. Introduction Kabul has experienced quick and uncontrolled population growth in consequence of due high population growth in Afghanistan [1]. A feasibility study for the extension of the Kabul water supply system, conducted in 2004, shows an estimated population in 2015 of 4,089,000, with water demand about 123.4 million m3/year [2]. However, the estimated groundwater availability in Kabul city, being approximately 44 million m3/year, can only supply around 2 million inhabitants at a modest per capita consumption of 50 lit/day [8]. Besides the insufficient water resource, Kabul is one of the least developed cities of the world regarding access to clean water supplies and effective sanitation [3]. Kabul Basin consists of sand, gravel conglomerate and loess loam, which have a particularly good filtration capacity. The main sources of pollution are drainage pit latrines, road site ditches, sewerage, leaking septic tanks, Kabul River and irrigation channels. Kabul city has no general waste water treatment. The other pollution sources, which contaminate the Published by Kazakh-German University, Almaty / Kazakhstan 4 groundwater within Kabul Basin, are sewage absorption wells, existing solid disposal, uncontrolled spreading of waste material, lack of a central sewerage system, overexploitation of groundwater, lack of water distribution pipelines, low public awareness of water related quality problems. Use of fertilizer for agriculture and existence of landfill sites in high permeability areas cause to pollute groundwater. In addition, low annual precipitation and low groundwater recharge coupled with groundwater extraction result in a negative balance between extractions and recharge. This means that current groundwater extraction is unsustainable, and the reduced groundwater volumes are unable to dilute increasing groundwater pollution. The objective of the present analysis is to assess current status and trends of groundwater and explore other sources of drinking water outside the Kabul city. The study uses various reports and data sets from different sources to assess the current status and provide future recommendations. Understanding the current situation will help to develop the resource in a sustainable way and also provide an example on groundwater resource management from a quickly developing region with major conflicts and few similar reported studies. 2. Study area 2.1. Climate and hydrology In Kabul, the air temperature ranges from a mean monthly low in January of -7 ˚C to a mean monthly high in July of 32 ˚C. The mean annual precipitation in Kabul is 300 mm. The annual evaporation rates in Kabul Basin are approximately 1,600 mm. Three rivers enter the Kabul city region: Kabul River, Paghman River and Logar River. The Kabul River enters the Kabul Basin from the south, and flows to the north about 21 km to the city of Kabul, and then flows to east. The Paghman River flows eastwardly from the Paghman Mountains and enters the Kabul River in the city of Kabul near the point where the Kabul River begins to flow east. The Logar River, a large tributary to the Kabul River, enters the Kabul City from south through a steeply cut valley and flows northward for about 28 km. The Logar River enters the Kabul River at the eastern edge of the city of Kabul, about 17 km downstream of the mouth of the Paghman River. 2.2. Geology and Hydrogeology of Kabul Basin Kabul city is located mainly in the flat Kabul Basin and it is surrounded and underlain by mountain ranges composed mainly of a variety of metamorphic rocks. The Kabul Basin is a basin structure that arose as a result of plate movements during the Late Palaeocene (early Tertiary) time. These rocks are part of the Kabul block and are intersected by the faults of the Herat-Bamyan-Panjsher main fault in the west and north-west, the Sorobi fault in the east, and the Chaman fault system in the south-east. The surrounded mountain ranges and bedrock are composed generally of a variety of metamorphic rocks, including gneiss, amphibolite, quartzite, slates, schist, marble, sandstone, mica of Precambrian age and consolidated rocks (limestone, dolomite) of Perm-Triassic age. The filling of the Kabul Basin itself consists of an Central Asian Journal of Water Research (2017) 3(2): 3-11 Special Issue on Water Use Management Challenges in Central Asia and Afghanistan 5 accumulation of terrestrial and lacustrine sediments, mainly of Quaternary and Neogene ages unconsolidated and semi-consolidated lacustrine, fluvial and aeolian sedimentary rocks such as sand, gravel and silt [4,5,6]. The region outlining the Kabul aquifer is generally described as having four main Quaternary interconnected aquifers. The upper Kabul Basin (Darulaman-Paghman sub basin) has two aquifers lying along the course of the Paghman River and the upper course of the Kabul River. The lower Kabul Basin (Kabul-Logar sub-basin) has two aquifers lying along the course of the Logar River and the lower course of the Kabul River. For the water supply are mostly used the aquifers of Quaternary and the upper aquifer of Tertiary. The recharge condition of the groundwater system is characterized by following sources being 1) recharges from rivers bed, 2) direct recharge from precipitation excess, 3) foot hill recharge from snow melt, 4) recharge from irrigation channels. Also, recharge from water supply networks, percolation of sewage, leakage septic tank and pit latrines might occur. The highest river discharge period, when almost all of water flow occurs is in April-May when snow melt occurs, and this is also the most likely period for aquifer recharge. The recharge sources and rates are not well documented for the aquifer. 2.3. Present Quantity and Quality Status of the Kabul Basin aquifer The physical, chemical and microbiological parameters of Kabul groundwater were analysed in the last 16 years by different organizations (Danish Committee for Aid to Afghan Refugees (DACAAR), Afghan Geological Survey, United States Geological Survey (USGS), Bundesanstalt für Geowissenschaften Und Rohstoffe (BGR), Japan International Cooperation Agency (JICA), etc.). The conducted tests show that nitrate and boron concentration are progressively increasing in the urban area. The tests also indicated that other harmful elements such as sulphate, chloride, boron, sodium and others are also progressively increasing [5, 6]. 3. Results and discussion 3.1. Groundwater Quantity Changes In recent years, a severe decline in a groundwater level has been observed (Table 1). A comparison of data of water levels from the Mack et al. [5] study with the water levels reported by Myslil et al. 1982 [6] indicates that water levels have declined by more than 10 m in foothill areas and 5 to 6 m in the area of the city of Kabul. Water levels have declined by more than 15 m in the upper the Kabul Basin areas from 2003 to 2016 [7]. The reason for a lowered groundwater level is the increase in the number of inhabitants which has doubled since 1990s. The rate of groundwater-level decline in the city increased (1.7 m/year on average) from 2008 to 2016. Many supply wells were installed only a few meters below the water table and are vulnerable to seasonal drying and now 33% of them are not in operation. Groundwater resources in the city of Kabul clearly face long-term sustainability concerns, such as increasing numbers of shallow water-supply wells going dry, whereas fewer issues with long- term water sustainability may have occurred in the northern Kabul Basin [8]. Central Asian Journal of Water Research (2017) 3(2): 3-11 Special Issue on Water Use Management Challenges in Central Asia and Afghanistan 6 Table 1. Decrease of water level in last 34 years [6,7,9] Year Water level change (m) Decline (m/year) 1982 – 2003 6 0.28 2003 – 2016 15 1.15 3.2. Groundwater quality changes The water quality investigations show a negative trend indicating that groundwater pollution has gradually increased. The water quality analyses show a great variation of groundwater quality especially in urban areas [4].